Zupaysaurus rougieri is an early neotheropod from the middle Norian Los Colorados Formation of northwestern Argentina represented by an almost complete skull and several postcranial bones. Allosauridae share with Coelurosauria a medially open maxillary antrum (evolved independently in Metriacanthosauridae and Eocarcharia). Monolophosaurus, Acrocanthosauridae and Allosauridae also share with basal Coelurosauria (Zuolong, Tanycolagreus, Tyrannosauroidea, Ornitholestes) a robust dorsal ramus of quadratojugal, forming a clade Euavetheropoda.
Megalosauridae, Monolophosaurus, Acrocanthosauridae and Allosauridae share with Coelurosauria a posteroventrally expanded surangular contact of dentary and a metacarpal IV less than 25% of metacarpal III or absent, forming a clade Avetheropoda. The above basal tetanurans and Monolophosaurus also share with Coelurosauria a maxillary fenestra. Piatnitzkysauridae, Metriacanthosauridae, Neovenator, Megaraptora, Megalosauridae, Acrocanthosauridae (Acrocanthosaurus, Eocarcharia) and Allosauridae (Allosaurus, Saurophaganax) share with basal Coelurosauria (Zuolong, Tanycolagreus, Coelurus, Tyrannosauroidea) a lesser trochanter extending proximally to the middle of femoral head (lesser trochanter extends proximally to the dorsal margin of femoral head in Megaraptora, Tyrannosauridae, and ornithomimosaur Beishanlong). Spinosauridae and Carcharodontosauridae (except Acrocanthosaurus and Eocarcharia) possess a lesser trochanter extending proximally to the ventral margin of femoral head and lack a maxillary fenestra, suggesting that they are the most basal tetanurans.
Sinosaurus retains a distally expanded scapula of the most basal neotheropods but shares with Ceratosauria & Tetanurae a large lesser trochanter, suggesting that it is more derived than the former but less derived than the latter. Cryolophosaurus possesses a small lesser trochanter, indicating it is among the most basal neotheropods (Coelophysis, Dilophosaurus). This presentation re-evaluates the phylogeny of non-coelurosaurian Tetanurae by re-examining highly distinct and size- and ecomorphology-independent states of several characters used in previous analyses. However, the positions of genera Cryolophosaurus, Sinosaurus, Monolophosaurus and Acrocanthosaurus and clade Megaraptora remain controversial and a few phylogenetic analyses question the monophyly of both Megalosauroidea and Allosauroidea. A majority of recent phylogenetic analyses of Tetanurae (Dinosauria: Theropoda) place basal (= non-coelurosaurian) tetanurans into clades Megalosauroidea and Allosauroidea forming successively closer outgroups to Coelurosauria.
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